1. Title: Lab 13 Magnetic Potential Energy Lab
Name: Qiwen Ye (Sherry)Lab partners names: Jae Yoo, Chandler
Date: 10-Oct-2016
2. Purpose
In this lab, we studied the conservation of energy and determined the relationship between kinetic energy, magnetic potential energy and total energy of the system.
3. Introduction
In order to verify the conservation of energy in the system, we used a friction less cart with a strong magnet on one end approaches a fixed magnet of the same polarity. The carts kinetic energy is momentarily zero and all of the energy in the system is stored in the magnetic field as magnetic potential energy, transformed back to kinetic energy. Because there is no equation for magnetic potential energy that we used the relationship:
About the interaction force F, we used the relationship in the triangle to find that F=mgsina. Here is the example how to calculate the magnetic force.
We used a gilder on an air track as our cart on a friction less surface. We provided an angle between the track and the lab table. If we raise one end of the air track the cart will end up at some equilibrium position, where the magnetic repulsion force between the two magnets will equal the gravitational force component on the cart parallel to the track. We used iPhone Compass app to measure the angle to +/-0.1 degree.
5. Measured Data
We did the same experiment five times in different angles, that we measured the angles and distance between magnet r. And, we measured the cart is m=338 g.
6. Calculated Data
About the magnetic force, we used that equation F=mgsina to get that. m=338g, g=9.8m/s^2, and the angle a is shown above. Therefore, we got five different values of magnetic force by five different angles.
7. Graph
By using the values of magnetic force F and distance between magnetic r, we did the graph of F vs. r. We assume that the relationship takes the form of a power law: F=Ar^n. A=0.0006413, n=-1.517.
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| A=0.0006413, n=-1.517 |
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| Position vs. time |
Then, we used the relationship to find the magnetic potential energy:
After we created the new Calculated Column in LogPro that we got the graph of magnetic potential energy and kinetic energy.
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| Blue:Total Energy Purple: Kinetic Energy Green: Magnetic Potential Energy |
In the graph F vs r, we determined that magnetic force F is decreasing by the distance r become bigger. The total energy is almost a straight line, it means that the energy is conservation. The kinetic energy and magnetic potential energy is opposite, because the conservation energy.
9 Conclusion
In this experiment, we learned the magnetic conservation of energy, which the magnetic energy transform to the kinetic energy. However, the line of total energy goes down shows that some energy disappeared when the cart was going down. The track we used is not exactly friction less, and the air-resistance may cause the energy loss. Overall, this experiment is successful.
9 Conclusion
In this experiment, we learned the magnetic conservation of energy, which the magnetic energy transform to the kinetic energy. However, the line of total energy goes down shows that some energy disappeared when the cart was going down. The track we used is not exactly friction less, and the air-resistance may cause the energy loss. Overall, this experiment is successful.
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